1. Field of the Invention
This invention relates generally to damper devices for controlling the opening rate of an openable object such as a cup holder, ashtray, glove compartment door, or the like relative to a main body. More particularly, the present invention relates to an improved air damper assembly which includes a piston head having a molded channel therein and a lip-like seal member disposed around the connecting member of the piston head so as to form a continuous seal therebetween and thereby control the dampening rate of the openable object.
2. Description of the Prior Art
As is generally well-known in the art, if an openable object is allowed to abruptly open relative to its main body the impact between them may not only cause damage to occur so as to possibly destroy both of them, but can also produce vibration and noise to render the contents stored within the openable object to fall out and become scattered. When the openable object is, for instance, a glove compartment door mounted in the dashboard of an automotive vehicle, the sudden impact opening may cause the items therein to be tossed or thrown all over the passenger, seat, and floor of the car. It will be appreciated that similar problems can also occur when the openable object is an ashtray, cup holder, and the like.
A state-of-the-art search directed to the subject matter of this application in the U.S. Patent and Trademark Office uncovered the following U.S. Letters Patent:
______________________________________ 2,497,425 5,163,204 4,248,444 5,165,124 4,428,567 5,220,706 4,938,324 5,265,710 ______________________________________
There is disclosed in U.S. Pat. No. 4,428,567 to J. P. Fournales issued on Jan. 31, 1984, a combined shock absorber and suspension device for a vehicle which includes an annular flexible lip 39 and a bypass conduit 40 formed within the piston 17 and bores 20. During expansion of the device when the piston moves in the direction of the arrow F, the lip 39 contacts the interior peripheral wall of the cylinder 1 and the fluid in the space 41 can only flow in the bypass conduit 40 and the bores 20. On the other hand, during compression of the device when the piston moves in the direction opposite the arrow F the lip 39 is retracted so as to allow the fluid to bleed past the lip 39 and through the annular space defined between the outer surface of the lip and the internal peripheral wall of the cylinder 1 and into the space 41, as well as through the bores 20.
There is disclosed in U.S. Pat. No. 4,938,324 to L. J. Van Dyke issued on Jul. 3, 1990, an automatic derailleur shifter for a bicycle which includes a movable piston 42 and a resilient, radially outwardly flared skirt 74 seated thereon. When the piston 42 is moved downwardly in the direction of the arrow 86, the flared skirt 74 of the annular seal will scrape against the inner peripheral wall of the cylinder 14 and all the fluid is forced through the annular fluid passage 68. When the piston 42 is moved upwardly in the direction of the arrow 78, the fluid will also pass through the passage 68 as well as bypassing over the flared skirt 74 through the clearance space 54 which is defined between the outer periphery of the fixed piston element 44 and the inner peripheral wall of the cylinder 14.
In U.S. Pat. No. 5,163,204 to C. B. Jackson issued on Nov. 17, 1992, there is taught a marine door movement control apparatus which includes a cylinder 21 and a piston 50 having seals 57, 58 seated thereon. An axial orifice 63 is provided which extends longitudinally through the piston 50. A radial orifice 64 is provided which communicates between a through-hole 51 in the piston 50 and the space 59 between the seals 57 and 58. The radial orifice 64 functions only when the piston 50 is moved in the direction of the arrow 62. Thus, when the piston 50 is moved in the direction of the arrow 62, fluid flows through both the orifices 64 and 63. However, when the piston is moved in the direction of the arrow 61, fluid can only flow through the orifice 63.
In U.S. Pat. No. 2,497,425 to A. P. Terry issued on Feb. 14, 1950, there is taught a flue damper which includes a cam track 12 and a cam follower pin 13 disposed on a stem member 11. A latching mechanism is formed of a sector-shaped latch 24 and a catch 26 in which the latch 24 is arranged to engage when the latch is directed inwardly of the flue.
In U.S. Pat. No. 4,248,444 to P. C. Johnson issued on Feb. 3, 1981, there is described a steering mechanism for a hospital-type carriage such as a four-wheeled mobile stretcher which includes a cam slide 62 in a mechanism for quickly disconnecting a caster of the carriage from a chain so as to render it freely swivelable. The cam slide 62 has an irregular, closed slot-type cam recess 64 formed therein which is used to receive a pin-like projection 66. The engagement of the projection 66 with the various surfaces of the inner portion 68 of the slide 62 will move the cam slide in various transverse directions.
In U.S. Pat. No. 5,165,124 to H. Li issued on Nov. 24, 1992, there is described a lifting gate controlling mechanism for controlling the front lifting gate of a baby's crib. The lifting gate is movably held by a pair of upper sliding blocks 6 and a pair of lower sliding blocks 7. Each of the upper sliding blocks 6 is secured to a respective upper mounting bar 4 for holding the lifting gate. A P-shaped sliding track 42 is formed on the front face of the mounting bars 4. A sliding rod 63 is joined at its one end to the lower end of the sliding block 6 and has an opposite end which is inserted in the sliding track 42 and moved slidably therein.
Further, there is shown in U.S. Pat. No. 5,265,710 to Gabas et al. issued on Nov. 30, 1993, a hydraulic self-adjusting housing for clutch control cables which is formed with a main housing CP. The housing has a longitudinal passage 4 through which communication may be established between the chambers C1 and C2. Art adjusting rod VR has a front end attached to the cable linked with the clutch pedal and a second end attached to the piston formed by shut-off valve VC. A control spring RR permanently pulls against the cable through the rod VR.
Finally, there is disclosed in U.S. Pat. No. 5,220,706 to S. L. Bivens issued on Jun. 22, 1993, and assigned to the same assignee as in the present invention an air damper utilizing only recirculating internal air for dampening in one direction the movement of an openable object. This '706 patent is hereby incorporated by reference. The air damper includes inner and outer cylinder members, primary and secondary shafts, first and second controllable orifice structures, primary and secondary end caps, and primary and secondary compression springs.
Heretofore, there have been attempts made in the prior art to provide damper devices for absorbing the impact created between the main body and the openable object so as to avoid these types of problems. Some of these prior art damper devices suffer from the disadvantage that they require the use of a small vent hole formed in the endwall of the damper housing. As a result, these prior art devices are susceptible to the problem that foreign material from the outside environment can plug or block the vent holes so as to eliminate the dampening effect. Further, these existing designs are typically constructed of a piston rod having a pair of axially spaced-apart disc-like members which are formed integrally adjacent its front end and which are connected by a connecting member of reduced diameter, and a lip seal disposed around the connecting member for slidable movement between the disc-like members. Since there is not a continuous seal between the inner diameter of the lip seal and the outer diameter of the connecting member, there will be experienced a slight jump or jerking motion during the initial release of the openable object while a seal is being created between the outer surface of the lip seal and the inner surface of one of the disc-like members.
There is also known in the prior art a damper device having a "push-push" type of locking device formed by means of a heart-shaped cam part, a follower pin, and a retaining clip as is shown and described in U.S. Pat. No. 4,948,103 to P. J. Bowden et al. issued on Aug. 14, 1990, and assigned to the same assignee as in the present invention. Since the follower pin follows the heart-shaped pattern and pivots from a fixed point, this type of existing design tends to cause latch inconsistencies and occasionally becomes disassembled during its operation. In particular, the latching malfunction will be mainly due to (1) skipping when the follower pin will completely skip the V-shaped portion of the cam part and thus no latching will occur, and (2) sticking when the follower pin will become stuck in the V-shaped portion of the cam part and thus unlatching will not occur.
It would therefore be desirable to provide an improved air damper assembly of a unique construction like that of the present invention which includes a piston head having a molded channel therein and a lip seal disposed around the connecting member of the piston head to form a continuous seal therebetween so as to control the dampening rate of openable objects. It would also be expedient to provide an air damper assembly with a one-piece diamond-shaped latching member encapsulated by the damper housing so as to prevent disassembly during its operation. The latching member in the damper assembly of the present invention represents a significant improvement over the locking device described in the above-mentioned '103 patent.